# Fall SAVY 2017, Day 3- Journey into the Universe: Astronomy 101 (3rd/4th)

Posted by on Monday, October 9, 2017 in Grade 3, Grade 4, SAVY blog.

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WEEK 3
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Today in Planetary Astronomy we talked about big numbers and orbits!

In most sciences and honestly in anything where one deals with large numbers, scientific notation is an efficient and necessary way to not have to write tons of zeros. We went over how to write big number scientific notation (we didn’t deal with numbers smaller than zero at this time) and talked about the names of large numbers (Wikipedia article: Names of Large Numbers. We also estimated the number of stars in the Universe (~1×10^22 = ~10×10^21 = ~10 sextillion!). I mentioned something about thinking about how many planets that means there are and then the possibility of aliens so that might be a fun thing to discuss with your student!
We had a quick segue into solar sails as possible transportation which was pretty cool. Here’s a quick video about them: What is a Solar Sail? You can also see fictionalized examples of them in Disney’s “Treasure Planet” 😉

After a break, we hit the computer lab for some simulation experiments! We needed to look at orbits so we used the <a href=“https://phet.colorado.edu/“PhET simulation Gravity and Orbits to examine how mass, distance, and velocity are related to each other. Students enjoyed orbiting and then crashing planets together 🙂 They also carried out trials and worked on what sorts of things a scientist would record and draw.

Next week we’ll look at WHY gravity happens therefore space-time fun will be had! We’ll also start investigating extrasolar planets in more depth.

One quick thing to note: please share the info on this blog with your students – they especially liked the stuff from week 2 (planetary formation) and wanted to see it again

– Dr. G 🙂